a) Field of the Disclosure
This disclosure relates to the field of hydrodynamic bore seals, and in particular to layered finger seals of a novel design and arrangement.
b) Background Art
Some examples of dry running seals to seal against leakage of a compressed gas include finger seals, brush seals and labyrinth seals. Typically, these seals are used in turbines, or other high-temperature, high-speed applications where lubricated seals or positive seals fail. Some examples of finger seals are described in patents such as US 2008/0122183, U.S. Pat. No. 6,196,550, U.S. Pat. No. 5,108,116, and U.S. Pat. No. 6,736,401.
In patent application US 2008/0122183 is disclosed hydrodynamic sealing pads comprising one or two taper angles, one taper angle in the direction of shaft speed (tangential) and the other taper angle in the axial direction. The taper in the tangential direction to rotation allows for an increasing hydrodynamic lift due to increasing RPM of the shaft being sealed. The taper in the axial direction results in a desirable lifting force due only to differential pressure. The two taper angles could be combined or used separately to create a more desirable operating range of RPMs and pressures for a given application.